Busy Bee Physics (Popularity: )
http://www.busy-bee-physics.com/ offers information and a collection of links for Newton's three laws of motion, electromegnetism, aerodynamics, and Einstein's theory of relativity.
Physics.org (Popularity: )
http://www.physics.org/ searchable database of resources from the Institute of Physics which matches user queries to handpicked sites. Also includes Physics Life animation.